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Comparing AnyEvent/README (file contents):
Revision 1.21 by root, Sat May 17 21:34:15 2008 UTC vs.
Revision 1.32 by root, Fri Oct 3 07:19:23 2008 UTC

…		…
5	loops	5	loops
6		6
7	SYNOPSIS	7	SYNOPSIS
8	use AnyEvent;	8	use AnyEvent;
9		9
10	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	10	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub { ... });
11	...
12	});
13		11
14	my $w = AnyEvent->timer (after => $seconds, cb => sub {	12	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		13	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		14
		15	print AnyEvent->now; # prints current event loop time
		16	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		17
		18	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		19
		20	my $w = AnyEvent->child (pid => $pid, cb => sub {
		21	my ($pid, $status) = @_;
15	...	22	...
16	});	23	});
17		24
18	my $w = AnyEvent->condvar; # stores whether a condition was flagged	25	my $w = AnyEvent->condvar; # stores whether a condition was flagged
19	$w->send; # wake up current and all future recv's	26	$w->send; # wake up current and all future recv's
20	$w->recv; # enters "main loop" till $condvar gets ->send	27	$w->recv; # enters "main loop" till $condvar gets ->send
		28	# use a condvar in callback mode:
		29	$w->cb (sub { $_[0]->recv });
		30
		31	INTRODUCTION/TUTORIAL
		32	This manpage is mainly a reference manual. If you are interested in a
		33	tutorial or some gentle introduction, have a look at the AnyEvent::Intro
		34	manpage.
21		35
22	WHY YOU SHOULD USE THIS MODULE (OR NOT)	36	WHY YOU SHOULD USE THIS MODULE (OR NOT)
23	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	37	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
24	nowadays. So what is different about AnyEvent?	38	nowadays. So what is different about AnyEvent?
25		39
26	Executive Summary: AnyEvent is compatible, AnyEvent is *free of	40	Executive Summary: AnyEvent is compatible, AnyEvent is *free of
27	policy* and AnyEvent is small and efficient.	41	policy* and AnyEvent is small and efficient.
28		42
29	First and foremost, AnyEvent is not an event model itself, it only	43	First and foremost, AnyEvent is not an event model itself, it only
30	interfaces to whatever event model the main program happens to use in a	44	interfaces to whatever event model the main program happens to use, in a
31	pragmatic way. For event models and certain classes of immortals alike,	45	pragmatic way. For event models and certain classes of immortals alike,
32	the statement "there can only be one" is a bitter reality: In general,	46	the statement "there can only be one" is a bitter reality: In general,
33	only one event loop can be active at the same time in a process.	47	only one event loop can be active at the same time in a process.
34	AnyEvent helps hiding the differences between those event loops.	48	AnyEvent cannot change this, but it can hide the differences between
		49	those event loops.
35		50
36	The goal of AnyEvent is to offer module authors the ability to do event	51	The goal of AnyEvent is to offer module authors the ability to do event
37	programming (waiting for I/O or timer events) without subscribing to a	52	programming (waiting for I/O or timer events) without subscribing to a
38	religion, a way of living, and most importantly: without forcing your	53	religion, a way of living, and most importantly: without forcing your
39	module users into the same thing by forcing them to use the same event	54	module users into the same thing by forcing them to use the same event
40	model you use.	55	model you use.
41		56
42	For modules like POE or IO::Async (which is a total misnomer as it is	57	For modules like POE or IO::Async (which is a total misnomer as it is
43	actually doing all I/O synchronously...), using them in your module is	58	actually doing all I/O synchronously...), using them in your module is
44	like joining a cult: After you joined, you are dependent on them and you	59	like joining a cult: After you joined, you are dependent on them and you
45	cannot use anything else, as it is simply incompatible to everything	60	cannot use anything else, as they are simply incompatible to everything
46	that isn't itself. What's worse, all the potential users of your module	61	that isn't them. What's worse, all the potential users of your module
47	are also forced to use the same event loop you use.	62	are also forced to use the same event loop you use.
48		63
49	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	64	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
50	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	65	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
51	with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if your	66	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if your
52	module uses one of those, every user of your module has to use it, too.	67	module uses one of those, every user of your module has to use it, too.
53	But if your module uses AnyEvent, it works transparently with all event	68	But if your module uses AnyEvent, it works transparently with all event
54	models it supports (including stuff like POE and IO::Async, as long as	69	models it supports (including stuff like IO::Async, as long as those use
55	those use one of the supported event loops. It is trivial to add new	70	one of the supported event loops. It is trivial to add new event loops
56	event loops to AnyEvent, too, so it is future-proof).	71	to AnyEvent, too, so it is future-proof).
57		72
58	In addition to being free of having to use *the one and only true event	73	In addition to being free of having to use *the one and only true event
59	model*, AnyEvent also is free of bloat and policy: with POE or similar	74	model*, AnyEvent also is free of bloat and policy: with POE or similar
60	modules, you get an enourmous amount of code and strict rules you have	75	modules, you get an enormous amount of code and strict rules you have to
61	to follow. AnyEvent, on the other hand, is lean and up to the point, by	76	follow. AnyEvent, on the other hand, is lean and up to the point, by
62	only offering the functionality that is necessary, in as thin as a	77	only offering the functionality that is necessary, in as thin as a
63	wrapper as technically possible.	78	wrapper as technically possible.
64		79
		80	Of course, AnyEvent comes with a big (and fully optional!) toolbox of
		81	useful functionality, such as an asynchronous DNS resolver, 100%
		82	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		83	such as Windows) and lots of real-world knowledge and workarounds for
		84	platform bugs and differences.
		85
65	Of course, if you want lots of policy (this can arguably be somewhat	86	Now, if you do want lots of policy (this can arguably be somewhat
66	useful) and you want to force your users to use the one and only event	87	useful) and you want to force your users to use the one and only event
67	model, you should not use this module.	88	model, you should not use this module.
68		89
69	DESCRIPTION	90	DESCRIPTION
70	AnyEvent provides an identical interface to multiple event loops. This	91	AnyEvent provides an identical interface to multiple event loops. This
…		…
99	starts using it, all bets are off. Maybe you should tell their authors	120	starts using it, all bets are off. Maybe you should tell their authors
100	to use AnyEvent so their modules work together with others seamlessly...	121	to use AnyEvent so their modules work together with others seamlessly...
101		122
102	The pure-perl implementation of AnyEvent is called	123	The pure-perl implementation of AnyEvent is called
103	"AnyEvent::Impl::Perl". Like other event modules you can load it	124	"AnyEvent::Impl::Perl". Like other event modules you can load it
104	explicitly.	125	explicitly and enjoy the high availability of that event loop :)
105		126
106	WATCHERS	127	WATCHERS
107	AnyEvent has the central concept of a watcher, which is an object that	128	AnyEvent has the central concept of a watcher, which is an object that
108	stores relevant data for each kind of event you are waiting for, such as	129	stores relevant data for each kind of event you are waiting for, such as
109	the callback to call, the filehandle to watch, etc.	130	the callback to call, the file handle to watch, etc.
110		131
111	These watchers are normal Perl objects with normal Perl lifetime. After	132	These watchers are normal Perl objects with normal Perl lifetime. After
112	creating a watcher it will immediately "watch" for events and invoke the	133	creating a watcher it will immediately "watch" for events and invoke the
113	callback when the event occurs (of course, only when the event model is	134	callback when the event occurs (of course, only when the event model is
114	in control).	135	in control).
…		…
122	Many watchers either are used with "recursion" (repeating timers for	143	Many watchers either are used with "recursion" (repeating timers for
123	example), or need to refer to their watcher object in other ways.	144	example), or need to refer to their watcher object in other ways.
124		145
125	An any way to achieve that is this pattern:	146	An any way to achieve that is this pattern:
126		147
127	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	148	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
128	# you can use $w here, for example to undef it	149	# you can use $w here, for example to undef it
129	undef $w;	150	undef $w;
130	});	151	});
131		152
132	Note that "my $w; $w =" combination. This is necessary because in Perl,	153	Note that "my $w; $w =" combination. This is necessary because in Perl,
133	my variables are only visible after the statement in which they are	154	my variables are only visible after the statement in which they are
134	declared.	155	declared.
135		156
136	I/O WATCHERS	157	I/O WATCHERS
137	You can create an I/O watcher by calling the "AnyEvent->io" method with	158	You can create an I/O watcher by calling the "AnyEvent->io" method with
138	the following mandatory key-value pairs as arguments:	159	the following mandatory key-value pairs as arguments:
139		160
140	"fh" the Perl file handle (not file descriptor) to watch for events.	161	"fh" the Perl file handle (not file descriptor) to watch for events
		162	(AnyEvent might or might not keep a reference to this file handle).
141	"poll" must be a string that is either "r" or "w", which creates a	163	"poll" must be a string that is either "r" or "w", which creates a
142	watcher waiting for "r"eadable or "w"ritable events, respectively. "cb"	164	watcher waiting for "r"eadable or "w"ritable events, respectively. "cb"
143	is the callback to invoke each time the file handle becomes ready.	165	is the callback to invoke each time the file handle becomes ready.
144		166
145	Although the callback might get passed parameters, their value and	167	Although the callback might get passed parameters, their value and
…		…
152		174
153	Some event loops issue spurious readyness notifications, so you should	175	Some event loops issue spurious readyness notifications, so you should
154	always use non-blocking calls when reading/writing from/to your file	176	always use non-blocking calls when reading/writing from/to your file
155	handles.	177	handles.
156		178
157	Example:
158
159	# wait for readability of STDIN, then read a line and disable the watcher	179	Example: wait for readability of STDIN, then read a line and disable the
		180	watcher.
		181
160	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	182	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
161	chomp (my $input = <STDIN>);	183	chomp (my $input = <STDIN>);
162	warn "read: $input\n";	184	warn "read: $input\n";
163	undef $w;	185	undef $w;
164	});	186	});
…		…
173		195
174	Although the callback might get passed parameters, their value and	196	Although the callback might get passed parameters, their value and
175	presence is undefined and you cannot rely on them. Portable AnyEvent	197	presence is undefined and you cannot rely on them. Portable AnyEvent
176	callbacks cannot use arguments passed to time watcher callbacks.	198	callbacks cannot use arguments passed to time watcher callbacks.
177		199
178	The timer callback will be invoked at most once: if you want a repeating	200	The callback will normally be invoked once only. If you specify another
179	timer you have to create a new watcher (this is a limitation by both Tk	201	parameter, "interval", as a strictly positive number (> 0), then the
180	and Glib).	202	callback will be invoked regularly at that interval (in fractional
		203	seconds) after the first invocation. If "interval" is specified with a
		204	false value, then it is treated as if it were missing.
181		205
182	Example:	206	The callback will be rescheduled before invoking the callback, but no
		207	attempt is done to avoid timer drift in most backends, so the interval
		208	is only approximate.
183		209
184	# fire an event after 7.7 seconds	210	Example: fire an event after 7.7 seconds.
		211
185	my $w = AnyEvent->timer (after => 7.7, cb => sub {	212	my $w = AnyEvent->timer (after => 7.7, cb => sub {
186	warn "timeout\n";	213	warn "timeout\n";
187	});	214	});
188		215
189	# to cancel the timer:	216	# to cancel the timer:
190	undef $w;	217	undef $w;
191		218
192	Example 2:
193
194	# fire an event after 0.5 seconds, then roughly every second	219	Example 2: fire an event after 0.5 seconds, then roughly every second.
195	my $w;
196		220
197	my $cb = sub {
198	# cancel the old timer while creating a new one
199	$w = AnyEvent->timer (after => 1, cb => $cb);	221	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		222	warn "timeout\n";
200	};	223	};
201
202	# start the "loop" by creating the first watcher
203	$w = AnyEvent->timer (after => 0.5, cb => $cb);
204		224
205	TIMING ISSUES	225	TIMING ISSUES
206	There are two ways to handle timers: based on real time (relative, "fire	226	There are two ways to handle timers: based on real time (relative, "fire
207	in 10 seconds") and based on wallclock time (absolute, "fire at 12	227	in 10 seconds") and based on wallclock time (absolute, "fire at 12
208	o'clock").	228	o'clock").
…		…
220	on wallclock time) timers.	240	on wallclock time) timers.
221		241
222	AnyEvent always prefers relative timers, if available, matching the	242	AnyEvent always prefers relative timers, if available, matching the
223	AnyEvent API.	243	AnyEvent API.
224		244
		245	AnyEvent has two additional methods that return the "current time":
		246
		247	AnyEvent->time
		248	This returns the "current wallclock time" as a fractional number of
		249	seconds since the Epoch (the same thing as "time" or
		250	"Time::HiRes::time" return, and the result is guaranteed to be
		251	compatible with those).
		252
		253	It progresses independently of any event loop processing, i.e. each
		254	call will check the system clock, which usually gets updated
		255	frequently.
		256
		257	AnyEvent->now
		258	This also returns the "current wallclock time", but unlike "time",
		259	above, this value might change only once per event loop iteration,
		260	depending on the event loop (most return the same time as "time",
		261	above). This is the time that AnyEvent's timers get scheduled
		262	against.
		263
		264	*In almost all cases (in all cases if you don't care), this is the
		265	function to call when you want to know the current time.*
		266
		267	This function is also often faster then "AnyEvent->time", and thus
		268	the preferred method if you want some timestamp (for example,
		269	AnyEvent::Handle uses this to update it's activity timeouts).
		270
		271	The rest of this section is only of relevance if you try to be very
		272	exact with your timing, you can skip it without bad conscience.
		273
		274	For a practical example of when these times differ, consider
		275	Event::Lib and EV and the following set-up:
		276
		277	The event loop is running and has just invoked one of your callback
		278	at time=500 (assume no other callbacks delay processing). In your
		279	callback, you wait a second by executing "sleep 1" (blocking the
		280	process for a second) and then (at time=501) you create a relative
		281	timer that fires after three seconds.
		282
		283	With Event::Lib, "AnyEvent->time" and "AnyEvent->now" will both
		284	return 501, because that is the current time, and the timer will be
		285	scheduled to fire at time=504 (501 + 3).
		286
		287	With EV, "AnyEvent->time" returns 501 (as that is the current time),
		288	but "AnyEvent->now" returns 500, as that is the time the last event
		289	processing phase started. With EV, your timer gets scheduled to run
		290	at time=503 (500 + 3).
		291
		292	In one sense, Event::Lib is more exact, as it uses the current time
		293	regardless of any delays introduced by event processing. However,
		294	most callbacks do not expect large delays in processing, so this
		295	causes a higher drift (and a lot more system calls to get the
		296	current time).
		297
		298	In another sense, EV is more exact, as your timer will be scheduled
		299	at the same time, regardless of how long event processing actually
		300	took.
		301
		302	In either case, if you care (and in most cases, you don't), then you
		303	can get whatever behaviour you want with any event loop, by taking
		304	the difference between "AnyEvent->time" and "AnyEvent->now" into
		305	account.
		306
225	SIGNAL WATCHERS	307	SIGNAL WATCHERS
226	You can watch for signals using a signal watcher, "signal" is the signal	308	You can watch for signals using a signal watcher, "signal" is the signal
227	name without any "SIG" prefix, "cb" is the Perl callback to be invoked	309	name in uppercase and without any "SIG" prefix, "cb" is the Perl
228	whenever a signal occurs.	310	callback to be invoked whenever a signal occurs.
229		311
230	Although the callback might get passed parameters, their value and	312	Although the callback might get passed parameters, their value and
231	presence is undefined and you cannot rely on them. Portable AnyEvent	313	presence is undefined and you cannot rely on them. Portable AnyEvent
232	callbacks cannot use arguments passed to signal watcher callbacks.	314	callbacks cannot use arguments passed to signal watcher callbacks.
233		315
234	Multiple signal occurances can be clumped together into one callback	316	Multiple signal occurrences can be clumped together into one callback
235	invocation, and callback invocation will be synchronous. synchronous	317	invocation, and callback invocation will be synchronous. Synchronous
236	means that it might take a while until the signal gets handled by the	318	means that it might take a while until the signal gets handled by the
237	process, but it is guarenteed not to interrupt any other callbacks.	319	process, but it is guaranteed not to interrupt any other callbacks.
238		320
239	The main advantage of using these watchers is that you can share a	321	The main advantage of using these watchers is that you can share a
240	signal between multiple watchers.	322	signal between multiple watchers.
241		323
242	This watcher might use %SIG, so programs overwriting those signals	324	This watcher might use %SIG, so programs overwriting those signals
…		…
248		330
249	CHILD PROCESS WATCHERS	331	CHILD PROCESS WATCHERS
250	You can also watch on a child process exit and catch its exit status.	332	You can also watch on a child process exit and catch its exit status.
251		333
252	The child process is specified by the "pid" argument (if set to 0, it	334	The child process is specified by the "pid" argument (if set to 0, it
253	watches for any child process exit). The watcher will trigger as often	335	watches for any child process exit). The watcher will triggered only
254	as status change for the child are received. This works by installing a	336	when the child process has finished and an exit status is available, not
255	signal handler for "SIGCHLD". The callback will be called with the pid	337	on any trace events (stopped/continued).
256	and exit status (as returned by waitpid), so unlike other watcher types,	338
257	you can rely on child watcher callback arguments.	339	The callback will be called with the pid and exit status (as returned by
		340	waitpid), so unlike other watcher types, you can rely on child watcher
		341	callback arguments.
		342
		343	This watcher type works by installing a signal handler for "SIGCHLD",
		344	and since it cannot be shared, nothing else should use SIGCHLD or reap
		345	random child processes (waiting for specific child processes, e.g.
		346	inside "system", is just fine).
258		347
259	There is a slight catch to child watchers, however: you usually start	348	There is a slight catch to child watchers, however: you usually start
260	them after the child process was created, and this means the process	349	them after the child process was created, and this means the process
261	could have exited already (and no SIGCHLD will be sent anymore).	350	could have exited already (and no SIGCHLD will be sent anymore).
262		351
…		…
269	an AnyEvent program, you have to create at least one watcher before	358	an AnyEvent program, you have to create at least one watcher before
270	you "fork" the child (alternatively, you can call "AnyEvent::detect").	359	you "fork" the child (alternatively, you can call "AnyEvent::detect").
271		360
272	Example: fork a process and wait for it	361	Example: fork a process and wait for it
273		362
274	my $done = AnyEvent->condvar;	363	my $done = AnyEvent->condvar;
275		364
276	my $pid = fork or exit 5;	365	my $pid = fork or exit 5;
277		366
278	my $w = AnyEvent->child (	367	my $w = AnyEvent->child (
279	pid => $pid,	368	pid => $pid,
280	cb => sub {	369	cb => sub {
281	my ($pid, $status) = @_;	370	my ($pid, $status) = @_;
282	warn "pid $pid exited with status $status";	371	warn "pid $pid exited with status $status";
283	$done->send;	372	$done->send;
284	},	373	},
285	);	374	);
286		375
287	# do something else, then wait for process exit	376	# do something else, then wait for process exit
288	$done->recv;	377	$done->recv;
289		378
290	CONDITION VARIABLES	379	CONDITION VARIABLES
291	If you are familiar with some event loops you will know that all of them	380	If you are familiar with some event loops you will know that all of them
292	require you to run some blocking "loop", "run" or similar function that	381	require you to run some blocking "loop", "run" or similar function that
293	will actively watch for new events and call your callbacks.	382	will actively watch for new events and call your callbacks.
…		…
298	The instrument to do that is called a "condition variable", so called	387	The instrument to do that is called a "condition variable", so called
299	because they represent a condition that must become true.	388	because they represent a condition that must become true.
300		389
301	Condition variables can be created by calling the "AnyEvent->condvar"	390	Condition variables can be created by calling the "AnyEvent->condvar"
302	method, usually without arguments. The only argument pair allowed is	391	method, usually without arguments. The only argument pair allowed is
		392
303	"cb", which specifies a callback to be called when the condition	393	"cb", which specifies a callback to be called when the condition
304	variable becomes true.	394	variable becomes true, with the condition variable as the first argument
		395	(but not the results).
305		396
306	After creation, the conditon variable is "false" until it becomes "true"	397	After creation, the condition variable is "false" until it becomes
		398	"true" by calling the "send" method (or calling the condition variable
		399	as if it were a callback, read about the caveats in the description for
307	by calling the "send" method.	400	the "->send" method).
308		401
309	Condition variables are similar to callbacks, except that you can	402	Condition variables are similar to callbacks, except that you can
310	optionally wait for them. They can also be called merge points - points	403	optionally wait for them. They can also be called merge points - points
311	in time where multiple outstandign events have been processed. And yet	404	in time where multiple outstanding events have been processed. And yet
312	another way to call them is transations - each condition variable can be	405	another way to call them is transactions - each condition variable can
313	used to represent a transaction, which finishes at some point and	406	be used to represent a transaction, which finishes at some point and
314	delivers a result.	407	delivers a result.
315		408
316	Condition variables are very useful to signal that something has	409	Condition variables are very useful to signal that something has
317	finished, for example, if you write a module that does asynchronous http	410	finished, for example, if you write a module that does asynchronous http
318	requests, then a condition variable would be the ideal candidate to	411	requests, then a condition variable would be the ideal candidate to
…		…
323	you can block your main program until an event occurs - for example, you	416	you can block your main program until an event occurs - for example, you
324	could "->recv" in your main program until the user clicks the Quit	417	could "->recv" in your main program until the user clicks the Quit
325	button of your app, which would "->send" the "quit" event.	418	button of your app, which would "->send" the "quit" event.
326		419
327	Note that condition variables recurse into the event loop - if you have	420	Note that condition variables recurse into the event loop - if you have
328	two pieces of code that call "->recv" in a round-robbin fashion, you	421	two pieces of code that call "->recv" in a round-robin fashion, you
329	lose. Therefore, condition variables are good to export to your caller,	422	lose. Therefore, condition variables are good to export to your caller,
330	but you should avoid making a blocking wait yourself, at least in	423	but you should avoid making a blocking wait yourself, at least in
331	callbacks, as this asks for trouble.	424	callbacks, as this asks for trouble.
332		425
333	Condition variables are represented by hash refs in perl, and the keys	426	Condition variables are represented by hash refs in perl, and the keys
…		…
338		431
339	There are two "sides" to a condition variable - the "producer side"	432	There are two "sides" to a condition variable - the "producer side"
340	which eventually calls "-> send", and the "consumer side", which waits	433	which eventually calls "-> send", and the "consumer side", which waits
341	for the send to occur.	434	for the send to occur.
342		435
343	Example:	436	Example: wait for a timer.
344		437
345	# wait till the result is ready	438	# wait till the result is ready
346	my $result_ready = AnyEvent->condvar;	439	my $result_ready = AnyEvent->condvar;
347		440
348	# do something such as adding a timer	441	# do something such as adding a timer
…		…
356		449
357	# this "blocks" (while handling events) till the callback	450	# this "blocks" (while handling events) till the callback
358	# calls send	451	# calls send
359	$result_ready->recv;	452	$result_ready->recv;
360		453
		454	Example: wait for a timer, but take advantage of the fact that condition
		455	variables are also code references.
		456
		457	my $done = AnyEvent->condvar;
		458	my $delay = AnyEvent->timer (after => 5, cb => $done);
		459	$done->recv;
		460
		461	Example: Imagine an API that returns a condvar and doesn't support
		462	callbacks. This is how you make a synchronous call, for example from the
		463	main program:
		464
		465	use AnyEvent::CouchDB;
		466
		467	...
		468
		469	my @info = $couchdb->info->recv;
		470
		471	And this is how you would just ste a callback to be called whenever the
		472	results are available:
		473
		474	$couchdb->info->cb (sub {
		475	my @info = $_[0]->recv;
		476	});
		477
361	METHODS FOR PRODUCERS	478	METHODS FOR PRODUCERS
362	These methods should only be used by the producing side, i.e. the	479	These methods should only be used by the producing side, i.e. the
363	code/module that eventually sends the signal. Note that it is also the	480	code/module that eventually sends the signal. Note that it is also the
364	producer side which creates the condvar in most cases, but it isn't	481	producer side which creates the condvar in most cases, but it isn't
365	uncommon for the consumer to create it as well.	482	uncommon for the consumer to create it as well.
…		…
372	If a callback has been set on the condition variable, it is called	489	If a callback has been set on the condition variable, it is called
373	immediately from within send.	490	immediately from within send.
374		491
375	Any arguments passed to the "send" call will be returned by all	492	Any arguments passed to the "send" call will be returned by all
376	future "->recv" calls.	493	future "->recv" calls.
		494
		495	Condition variables are overloaded so one can call them directly (as
		496	a code reference). Calling them directly is the same as calling
		497	"send". Note, however, that many C-based event loops do not handle
		498	overloading, so as tempting as it may be, passing a condition
		499	variable instead of a callback does not work. Both the pure perl and
		500	EV loops support overloading, however, as well as all functions that
		501	use perl to invoke a callback (as in AnyEvent::Socket and
		502	AnyEvent::DNS for example).
377		503
378	$cv->croak ($error)	504	$cv->croak ($error)
379	Similar to send, but causes all call's to "->recv" to invoke	505	Similar to send, but causes all call's to "->recv" to invoke
380	"Carp::croak" with the given error message/object/scalar.	506	"Carp::croak" with the given error message/object/scalar.
381		507
…		…
427	(the loop doesn't execute once).	553	(the loop doesn't execute once).
428		554
429	This is the general pattern when you "fan out" into multiple	555	This is the general pattern when you "fan out" into multiple
430	subrequests: use an outer "begin"/"end" pair to set the callback and	556	subrequests: use an outer "begin"/"end" pair to set the callback and
431	ensure "end" is called at least once, and then, for each subrequest	557	ensure "end" is called at least once, and then, for each subrequest
432	you start, call "begin" and for eahc subrequest you finish, call	558	you start, call "begin" and for each subrequest you finish, call
433	"end".	559	"end".
434		560
435	METHODS FOR CONSUMERS	561	METHODS FOR CONSUMERS
436	These methods should only be used by the consuming side, i.e. the code	562	These methods should only be used by the consuming side, i.e. the code
437	awaits the condition.	563	awaits the condition.
…		…
453	(programs might want to do that to stay interactive), so *if you are	579	(programs might want to do that to stay interactive), so *if you are
454	using this from a module, never require a blocking wait*, but let	580	using this from a module, never require a blocking wait*, but let
455	the caller decide whether the call will block or not (for example,	581	the caller decide whether the call will block or not (for example,
456	by coupling condition variables with some kind of request results	582	by coupling condition variables with some kind of request results
457	and supporting callbacks so the caller knows that getting the result	583	and supporting callbacks so the caller knows that getting the result
458	will not block, while still suppporting blocking waits if the caller	584	will not block, while still supporting blocking waits if the caller
459	so desires).	585	so desires).
460		586
461	Another reason never to "->recv" in a module is that you cannot	587	Another reason never to "->recv" in a module is that you cannot
462	sensibly have two "->recv"'s in parallel, as that would require	588	sensibly have two "->recv"'s in parallel, as that would require
463	multiple interpreters or coroutines/threads, none of which	589	multiple interpreters or coroutines/threads, none of which
…		…
476		602
477	$bool = $cv->ready	603	$bool = $cv->ready
478	Returns true when the condition is "true", i.e. whether "send" or	604	Returns true when the condition is "true", i.e. whether "send" or
479	"croak" have been called.	605	"croak" have been called.
480		606
481	$cb = $cv->cb ([new callback])	607	$cb = $cv->cb ($cb->($cv))
482	This is a mutator function that returns the callback set and	608	This is a mutator function that returns the callback set and
483	optionally replaces it before doing so.	609	optionally replaces it before doing so.
484		610
485	The callback will be called when the condition becomes "true", i.e.	611	The callback will be called when the condition becomes "true", i.e.
486	when "send" or "croak" are called. Calling "recv" inside the	612	when "send" or "croak" are called, with the only argument being the
		613	condition variable itself. Calling "recv" inside the callback or at
487	callback or at any later time is guaranteed not to block.	614	any later time is guaranteed not to block.
488		615
489	GLOBAL VARIABLES AND FUNCTIONS	616	GLOBAL VARIABLES AND FUNCTIONS
490	$AnyEvent::MODEL	617	$AnyEvent::MODEL
491	Contains "undef" until the first watcher is being created. Then it	618	Contains "undef" until the first watcher is being created. Then it
492	contains the event model that is being used, which is the name of	619	contains the event model that is being used, which is the name of
…		…
566	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	693	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
567	do anything special (it does not need to be event-based) and let	694	do anything special (it does not need to be event-based) and let
568	AnyEvent decide which implementation to chose if some module relies on	695	AnyEvent decide which implementation to chose if some module relies on
569	it.	696	it.
570		697
571	If the main program relies on a specific event model. For example, in	698	If the main program relies on a specific event model - for example, in
572	Gtk2 programs you have to rely on the Glib module. You should load the	699	Gtk2 programs you have to rely on the Glib module - you should load the
573	event module before loading AnyEvent or any module that uses it:	700	event module before loading AnyEvent or any module that uses it:
574	generally speaking, you should load it as early as possible. The reason	701	generally speaking, you should load it as early as possible. The reason
575	is that modules might create watchers when they are loaded, and AnyEvent	702	is that modules might create watchers when they are loaded, and AnyEvent
576	will decide on the event model to use as soon as it creates watchers,	703	will decide on the event model to use as soon as it creates watchers,
577	and it might chose the wrong one unless you load the correct one	704	and it might chose the wrong one unless you load the correct one
578	yourself.	705	yourself.
579		706
580	You can chose to use a rather inefficient pure-perl implementation by	707	You can chose to use a pure-perl implementation by loading the
581	loading the "AnyEvent::Impl::Perl" module, which gives you similar	708	"AnyEvent::Impl::Perl" module, which gives you similar behaviour
582	behaviour everywhere, but letting AnyEvent chose is generally better.	709	everywhere, but letting AnyEvent chose the model is generally better.
		710
		711	MAINLOOP EMULATION
		712	Sometimes (often for short test scripts, or even standalone programs who
		713	only want to use AnyEvent), you do not want to run a specific event
		714	loop.
		715
		716	In that case, you can use a condition variable like this:
		717
		718	AnyEvent->condvar->recv;
		719
		720	This has the effect of entering the event loop and looping forever.
		721
		722	Note that usually your program has some exit condition, in which case it
		723	is better to use the "traditional" approach of storing a condition
		724	variable somewhere, waiting for it, and sending it when the program
		725	should exit cleanly.
583		726
584	OTHER MODULES	727	OTHER MODULES
585	The following is a non-exhaustive list of additional modules that use	728	The following is a non-exhaustive list of additional modules that use
586	AnyEvent and can therefore be mixed easily with other AnyEvent modules	729	AnyEvent and can therefore be mixed easily with other AnyEvent modules
587	in the same program. Some of the modules come with AnyEvent, some are	730	in the same program. Some of the modules come with AnyEvent, some are
…		…
590	AnyEvent::Util	733	AnyEvent::Util
591	Contains various utility functions that replace often-used but	734	Contains various utility functions that replace often-used but
592	blocking functions such as "inet_aton" by event-/callback-based	735	blocking functions such as "inet_aton" by event-/callback-based
593	versions.	736	versions.
594		737
		738	AnyEvent::Socket
		739	Provides various utility functions for (internet protocol) sockets,
		740	addresses and name resolution. Also functions to create non-blocking
		741	tcp connections or tcp servers, with IPv6 and SRV record support and
		742	more.
		743
595	AnyEvent::Handle	744	AnyEvent::Handle
596	Provide read and write buffers and manages watchers for reads and	745	Provide read and write buffers, manages watchers for reads and
597	writes.	746	writes, supports raw and formatted I/O, I/O queued and fully
		747	transparent and non-blocking SSL/TLS.
		748
		749	AnyEvent::DNS
		750	Provides rich asynchronous DNS resolver capabilities.
		751
		752	AnyEvent::HTTP
		753	A simple-to-use HTTP library that is capable of making a lot of
		754	concurrent HTTP requests.
598		755
599	AnyEvent::HTTPD	756	AnyEvent::HTTPD
600	Provides a simple web application server framework.	757	Provides a simple web application server framework.
601		758
602	AnyEvent::DNS
603	Provides asynchronous DNS resolver capabilities, beyond what
604	AnyEvent::Util offers.
605
606	AnyEvent::FastPing	759	AnyEvent::FastPing
607	The fastest ping in the west.	760	The fastest ping in the west.
608		761
		762	AnyEvent::DBI
		763	Executes DBI requests asynchronously in a proxy process.
		764
		765	AnyEvent::AIO
		766	Truly asynchronous I/O, should be in the toolbox of every event
		767	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		768	together.
		769
		770	AnyEvent::BDB
		771	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently
		772	fuses BDB and AnyEvent together.
		773
		774	AnyEvent::GPSD
		775	A non-blocking interface to gpsd, a daemon delivering GPS
		776	information.
		777
		778	AnyEvent::IGS
		779	A non-blocking interface to the Internet Go Server protocol (used by
		780	App::IGS).
		781
		782	AnyEvent::IRC
		783	AnyEvent based IRC client module family (replacing the older
609	Net::IRC3	784	Net::IRC3).
610	AnyEvent based IRC client module family.
611		785
612	Net::XMPP2	786	Net::XMPP2
613	AnyEvent based XMPP (Jabber protocol) module family.	787	AnyEvent based XMPP (Jabber protocol) module family.
614		788
615	Net::FCP	789	Net::FCP
…		…
620	High level API for event-based execution flow control.	794	High level API for event-based execution flow control.
621		795
622	Coro	796	Coro
623	Has special support for AnyEvent via Coro::AnyEvent.	797	Has special support for AnyEvent via Coro::AnyEvent.
624		798
625	AnyEvent::AIO, IO::AIO
626	Truly asynchronous I/O, should be in the toolbox of every event
627	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
628	together.
629
630	AnyEvent::BDB, BDB
631	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently
632	fuses IO::AIO and AnyEvent together.
633
634	IO::Lambda	799	IO::Lambda
635	The lambda approach to I/O - don't ask, look there. Can use	800	The lambda approach to I/O - don't ask, look there. Can use
636	AnyEvent.	801	AnyEvent.
		802
		803	ERROR AND EXCEPTION HANDLING
		804	In general, AnyEvent does not do any error handling - it relies on the
		805	caller to do that if required. The AnyEvent::Strict module (see also the
		806	"PERL_ANYEVENT_STRICT" environment variable, below) provides strict
		807	checking of all AnyEvent methods, however, which is highly useful during
		808	development.
		809
		810	As for exception handling (i.e. runtime errors and exceptions thrown
		811	while executing a callback), this is not only highly event-loop
		812	specific, but also not in any way wrapped by this module, as this is the
		813	job of the main program.
		814
		815	The pure perl event loop simply re-throws the exception (usually within
		816	"condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()",
		817	Glib uses "install_exception_handler" and so on.
		818
		819	ENVIRONMENT VARIABLES
		820	The following environment variables are used by this module or its
		821	submodules:
		822
		823	"PERL_ANYEVENT_VERBOSE"
		824	By default, AnyEvent will be completely silent except in fatal
		825	conditions. You can set this environment variable to make AnyEvent
		826	more talkative.
		827
		828	When set to 1 or higher, causes AnyEvent to warn about unexpected
		829	conditions, such as not being able to load the event model specified
		830	by "PERL_ANYEVENT_MODEL".
		831
		832	When set to 2 or higher, cause AnyEvent to report to STDERR which
		833	event model it chooses.
		834
		835	"PERL_ANYEVENT_STRICT"
		836	AnyEvent does not do much argument checking by default, as thorough
		837	argument checking is very costly. Setting this variable to a true
		838	value will cause AnyEvent to load "AnyEvent::Strict" and then to
		839	thoroughly check the arguments passed to most method calls. If it
		840	finds any problems it will croak.
		841
		842	In other words, enables "strict" mode.
		843
		844	Unlike "use strict", it is definitely recommended ot keep it off in
		845	production. Keeping "PERL_ANYEVENT_STRICT=1" in your environment
		846	while developing programs can be very useful, however.
		847
		848	"PERL_ANYEVENT_MODEL"
		849	This can be used to specify the event model to be used by AnyEvent,
		850	before auto detection and -probing kicks in. It must be a string
		851	consisting entirely of ASCII letters. The string "AnyEvent::Impl::"
		852	gets prepended and the resulting module name is loaded and if the
		853	load was successful, used as event model. If it fails to load
		854	AnyEvent will proceed with auto detection and -probing.
		855
		856	This functionality might change in future versions.
		857
		858	For example, to force the pure perl model (AnyEvent::Impl::Perl) you
		859	could start your program like this:
		860
		861	PERL_ANYEVENT_MODEL=Perl perl ...
		862
		863	"PERL_ANYEVENT_PROTOCOLS"
		864	Used by both AnyEvent::DNS and AnyEvent::Socket to determine
		865	preferences for IPv4 or IPv6. The default is unspecified (and might
		866	change, or be the result of auto probing).
		867
		868	Must be set to a comma-separated list of protocols or address
		869	families, current supported: "ipv4" and "ipv6". Only protocols
		870	mentioned will be used, and preference will be given to protocols
		871	mentioned earlier in the list.
		872
		873	This variable can effectively be used for denial-of-service attacks
		874	against local programs (e.g. when setuid), although the impact is
		875	likely small, as the program has to handle connection errors
		876	already-
		877
		878	Examples: "PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6" - prefer IPv4 over
		879	IPv6, but support both and try to use both.
		880	"PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to
		881	resolve or contact IPv6 addresses.
		882	"PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but
		883	prefer IPv6 over IPv4.
		884
		885	"PERL_ANYEVENT_EDNS0"
		886	Used by AnyEvent::DNS to decide whether to use the EDNS0 extension
		887	for DNS. This extension is generally useful to reduce DNS traffic,
		888	but some (broken) firewalls drop such DNS packets, which is why it
		889	is off by default.
		890
		891	Setting this variable to 1 will cause AnyEvent::DNS to announce
		892	EDNS0 in its DNS requests.
		893
		894	"PERL_ANYEVENT_MAX_FORKS"
		895	The maximum number of child processes that
		896	"AnyEvent::Util::fork_call" will create in parallel.
637		897
638	SUPPLYING YOUR OWN EVENT MODEL INTERFACE	898	SUPPLYING YOUR OWN EVENT MODEL INTERFACE
639	This is an advanced topic that you do not normally need to use AnyEvent	899	This is an advanced topic that you do not normally need to use AnyEvent
640	in a module. This section is only of use to event loop authors who want	900	in a module. This section is only of use to event loop authors who want
641	to provide AnyEvent compatibility.	901	to provide AnyEvent compatibility.
…		…
675		935
676	rxvt-unicode also cheats a bit by not providing blocking access to	936	rxvt-unicode also cheats a bit by not providing blocking access to
677	condition variables: code blocking while waiting for a condition will	937	condition variables: code blocking while waiting for a condition will
678	"die". This still works with most modules/usages, and blocking calls	938	"die". This still works with most modules/usages, and blocking calls
679	must not be done in an interactive application, so it makes sense.	939	must not be done in an interactive application, so it makes sense.
680
681	ENVIRONMENT VARIABLES
682	The following environment variables are used by this module:
683
684	"PERL_ANYEVENT_VERBOSE"
685	By default, AnyEvent will be completely silent except in fatal
686	conditions. You can set this environment variable to make AnyEvent
687	more talkative.
688
689	When set to 1 or higher, causes AnyEvent to warn about unexpected
690	conditions, such as not being able to load the event model specified
691	by "PERL_ANYEVENT_MODEL".
692
693	When set to 2 or higher, cause AnyEvent to report to STDERR which
694	event model it chooses.
695
696	"PERL_ANYEVENT_MODEL"
697	This can be used to specify the event model to be used by AnyEvent,
698	before autodetection and -probing kicks in. It must be a string
699	consisting entirely of ASCII letters. The string "AnyEvent::Impl::"
700	gets prepended and the resulting module name is loaded and if the
701	load was successful, used as event model. If it fails to load
702	AnyEvent will proceed with autodetection and -probing.
703
704	This functionality might change in future versions.
705
706	For example, to force the pure perl model (AnyEvent::Impl::Perl) you
707	could start your program like this:
708
709	PERL_ANYEVENT_MODEL=Perl perl ...
710		940
711	EXAMPLE PROGRAM	941	EXAMPLE PROGRAM
712	The following program uses an I/O watcher to read data from STDIN, a	942	The following program uses an I/O watcher to read data from STDIN, a
713	timer to display a message once per second, and a condition variable to	943	timer to display a message once per second, and a condition variable to
714	quit the program when the user enters quit:	944	quit the program when the user enters quit:
…		…
796	syswrite $txn->{fh}, $txn->{request}	1026	syswrite $txn->{fh}, $txn->{request}
797	or die "connection or write error";	1027	or die "connection or write error";
798	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1028	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
799		1029
800	Again, "fh_ready_r" waits till all data has arrived, and then stores the	1030	Again, "fh_ready_r" waits till all data has arrived, and then stores the
801	result and signals any possible waiters that the request ahs finished:	1031	result and signals any possible waiters that the request has finished:
802		1032
803	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1033	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
804		1034
805	if (end-of-file or data complete) {	1035	if (end-of-file or data complete) {
806	$txn->{result} = $txn->{buf};	1036	$txn->{result} = $txn->{buf};
…		…
814		1044
815	$txn->{finished}->recv;	1045	$txn->{finished}->recv;
816	return $txn->{result};	1046	return $txn->{result};
817		1047
818	The actual code goes further and collects all errors ("die"s,	1048	The actual code goes further and collects all errors ("die"s,
819	exceptions) that occured during request processing. The "result" method	1049	exceptions) that occurred during request processing. The "result" method
820	detects whether an exception as thrown (it is stored inside the $txn	1050	detects whether an exception as thrown (it is stored inside the $txn
821	object) and just throws the exception, which means connection errors and	1051	object) and just throws the exception, which means connection errors and
822	other problems get reported tot he code that tries to use the result,	1052	other problems get reported tot he code that tries to use the result,
823	not in a random callback.	1053	not in a random callback.
824		1054
…		…
867	over the event loops themselves and to give you an impression of the	1097	over the event loops themselves and to give you an impression of the
868	speed of various event loops I prepared some benchmarks.	1098	speed of various event loops I prepared some benchmarks.
869		1099
870	BENCHMARKING ANYEVENT OVERHEAD	1100	BENCHMARKING ANYEVENT OVERHEAD
871	Here is a benchmark of various supported event models used natively and	1101	Here is a benchmark of various supported event models used natively and
872	through anyevent. The benchmark creates a lot of timers (with a zero	1102	through AnyEvent. The benchmark creates a lot of timers (with a zero
873	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1103	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
874	which it is), lets them fire exactly once and destroys them again.	1104	which it is), lets them fire exactly once and destroys them again.
875		1105
876	Source code for this benchmark is found as eg/bench in the AnyEvent	1106	Source code for this benchmark is found as eg/bench in the AnyEvent
877	distribution.	1107	distribution.
…		…
992		1222
993	* You should avoid POE like the plague if you want performance or	1223	* You should avoid POE like the plague if you want performance or
994	reasonable memory usage.	1224	reasonable memory usage.
995		1225
996	BENCHMARKING THE LARGE SERVER CASE	1226	BENCHMARKING THE LARGE SERVER CASE
997	This benchmark atcually benchmarks the event loop itself. It works by	1227	This benchmark actually benchmarks the event loop itself. It works by
998	creating a number of "servers": each server consists of a socketpair, a	1228	creating a number of "servers": each server consists of a socket pair, a
999	timeout watcher that gets reset on activity (but never fires), and an	1229	timeout watcher that gets reset on activity (but never fires), and an
1000	I/O watcher waiting for input on one side of the socket. Each time the	1230	I/O watcher waiting for input on one side of the socket. Each time the
1001	socket watcher reads a byte it will write that byte to a random other	1231	socket watcher reads a byte it will write that byte to a random other
1002	"server".	1232	"server".
1003		1233
1004	The effect is that there will be a lot of I/O watchers, only part of	1234	The effect is that there will be a lot of I/O watchers, only part of
1005	which are active at any one point (so there is a constant number of	1235	which are active at any one point (so there is a constant number of
1006	active fds for each loop iterstaion, but which fds these are is random).	1236	active fds for each loop iteration, but which fds these are is random).
1007	The timeout is reset each time something is read because that reflects	1237	The timeout is reset each time something is read because that reflects
1008	how most timeouts work (and puts extra pressure on the event loops).	1238	how most timeouts work (and puts extra pressure on the event loops).
1009		1239
1010	In this benchmark, we use 10000 socketpairs (20000 sockets), of which	1240	In this benchmark, we use 10000 socket pairs (20000 sockets), of which
1011	100 (1%) are active. This mirrors the activity of large servers with	1241	100 (1%) are active. This mirrors the activity of large servers with
1012	many connections, most of which are idle at any one point in time.	1242	many connections, most of which are idle at any one point in time.
1013		1243
1014	Source code for this benchmark is found as eg/bench2 in the AnyEvent	1244	Source code for this benchmark is found as eg/bench2 in the AnyEvent
1015	distribution.	1245	distribution.
1016		1246
1017	Explanation of the columns	1247	Explanation of the columns
1018	sockets is the number of sockets, and twice the number of "servers"	1248	sockets is the number of sockets, and twice the number of "servers"
1019	(as each server has a read and write socket end).	1249	(as each server has a read and write socket end).
1020		1250
1021	create is the time it takes to create a socketpair (which is	1251	create is the time it takes to create a socket pair (which is
1022	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1252	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1023		1253
1024	request, the most important value, is the time it takes to handle a	1254	request, the most important value, is the time it takes to handle a
1025	single "request", that is, reading the token from the pipe and	1255	single "request", that is, reading the token from the pipe and
1026	forwarding it to another server. This includes deleting the old timeout	1256	forwarding it to another server. This includes deleting the old timeout
…		…
1090	and speed most when you have lots of watchers, not when you only have a	1320	and speed most when you have lots of watchers, not when you only have a
1091	few of them).	1321	few of them).
1092		1322
1093	EV is again fastest.	1323	EV is again fastest.
1094		1324
1095	Perl again comes second. It is noticably faster than the C-based event	1325	Perl again comes second. It is noticeably faster than the C-based event
1096	loops Event and Glib, although the difference is too small to really	1326	loops Event and Glib, although the difference is too small to really
1097	matter.	1327	matter.
1098		1328
1099	POE also performs much better in this case, but is is still far behind	1329	POE also performs much better in this case, but is is still far behind
1100	the others.	1330	the others.
1101		1331
1102	Summary	1332	Summary
1103	* C-based event loops perform very well with small number of watchers,	1333	* C-based event loops perform very well with small number of watchers,
1104	as the management overhead dominates.	1334	as the management overhead dominates.
		1335
		1336	SIGNALS
		1337	AnyEvent currently installs handlers for these signals:
		1338
		1339	SIGCHLD
		1340	A handler for "SIGCHLD" is installed by AnyEvent's child watcher
		1341	emulation for event loops that do not support them natively. Also,
		1342	some event loops install a similar handler.
		1343
		1344	SIGPIPE
		1345	A no-op handler is installed for "SIGPIPE" when $SIG{PIPE} is
		1346	"undef" when AnyEvent gets loaded.
		1347
		1348	The rationale for this is that AnyEvent users usually do not really
		1349	depend on SIGPIPE delivery (which is purely an optimisation for
		1350	shell use, or badly-written programs), but "SIGPIPE" can cause
		1351	spurious and rare program exits as a lot of people do not expect
		1352	"SIGPIPE" when writing to some random socket.
		1353
		1354	The rationale for installing a no-op handler as opposed to ignoring
		1355	it is that this way, the handler will be restored to defaults on
		1356	exec.
		1357
		1358	Feel free to install your own handler, or reset it to defaults.
1105		1359
1106	FORK	1360	FORK
1107	Most event libraries are not fork-safe. The ones who are usually are	1361	Most event libraries are not fork-safe. The ones who are usually are
1108	because they rely on inefficient but fork-safe "select" or "poll" calls.	1362	because they rely on inefficient but fork-safe "select" or "poll" calls.
1109	Only EV is fully fork-aware.	1363	Only EV is fully fork-aware.
…		…
1120	model than specified in the variable.	1374	model than specified in the variable.
1121		1375
1122	You can make AnyEvent completely ignore this variable by deleting it	1376	You can make AnyEvent completely ignore this variable by deleting it
1123	before the first watcher gets created, e.g. with a "BEGIN" block:	1377	before the first watcher gets created, e.g. with a "BEGIN" block:
1124		1378
1125	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1379	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1126		1380
1127	use AnyEvent;	1381	use AnyEvent;
1128		1382
1129	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1383	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1130	be used to probe what backend is used and gain other information (which	1384	be used to probe what backend is used and gain other information (which
1131	is probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1385	is probably even less useful to an attacker than PERL_ANYEVENT_MODEL),
		1386	and $ENV{PERL_ANYEGENT_STRICT}.
		1387
		1388	BUGS
		1389	Perl 5.8 has numerous memleaks that sometimes hit this module and are
		1390	hard to work around. If you suffer from memleaks, first upgrade to Perl
		1391	5.10 and check wether the leaks still show up. (Perl 5.10.0 has other
		1392	annoying mamleaks, such as leaking on "map" and "grep" but it is usually
		1393	not as pronounced).
1132		1394
1133	SEE ALSO	1395	SEE ALSO
		1396	Utility functions: AnyEvent::Util.
		1397
1134	Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk,	1398	Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk,
1135	Event::Lib, Qt, POE.	1399	Event::Lib, Qt, POE.
1136		1400
1137	Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event,	1401	Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event,
1138	AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl,	1402	AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl,
1139	AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE.	1403	AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE.
1140		1404
		1405	Non-blocking file handles, sockets, TCP clients and servers:
		1406	AnyEvent::Handle, AnyEvent::Socket.
		1407
		1408	Asynchronous DNS: AnyEvent::DNS.
		1409
1141	Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event,	1410	Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event,
1142		1411
1143	Nontrivial usage examples: Net::FCP, Net::XMPP2.	1412	Nontrivial usage examples: Net::FCP, Net::XMPP2, AnyEvent::DNS.
1144		1413
1145	AUTHOR	1414	AUTHOR
1146	Marc Lehmann <schmorp@schmorp.de>	1415	Marc Lehmann <schmorp@schmorp.de>
1147	http://home.schmorp.de/	1416	http://home.schmorp.de/
1148		1417

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Comparing AnyEvent/README (file contents): Revision 1.21 by root, Sat May 17 21:34:15 2008 UTC vs. Revision 1.32 by root, Fri Oct 3 07:19:23 2008 UTC

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Comparing AnyEvent/README (file contents):
Revision 1.21 by root, Sat May 17 21:34:15 2008 UTC vs.
Revision 1.32 by root, Fri Oct 3 07:19:23 2008 UTC